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Serologic testing of U.S. blood donations to identify SARS-CoV-2-reactive antibodies: December 2019-January 2020


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Sridhar V Basavaraju, Monica E Patton, Kacie Grimm, Mohammed Ata Ur Rasheed, Sandra Lester, Lisa Mills, Megan Stumpf, Brandi Freeman, Azaibi Tamin, Jennifer Harcourt, Jarad Schiffer, Vera Semenova, Han Li, Bailey Alston, Muyiwa Ategbole, Shanna Bolcen, Darbi Boulay, Peter Browning, Li Cronin, Ebenezer David, Rita Desai, Monica Epperson, Yamini Gorantla, Tao Jia, Panagiotis Maniatis, Kimberly Moss, Kristina Ortiz, So Hee Park, Palak Patel, Yunlong Qin, Evelene Steward-Clark, Heather Tatum, Andrew Vogan, Briana Zellner, Jan Drobeniuc, Matthew R P Sapiano, Fiona Havers, Carrie Reed, Susan Gerber, Natalie J Thornburg, Susan L Stramer. 2020. "Serologic testing of U.S. blood donations to identify SARS-CoV-2-reactive antibodies": December 2019-January 2020, Clinical Infectious Diseases, ciaa1785,



SARS-CoV-2, the virus that causes COVID-19 disease, was first identified in Wuhan, China in December 2019, with subsequent worldwide spread. The first U.S. cases were identified in January 2020.


To determine if SARS-CoV-2 reactive antibodies were present in sera prior to the first identified case in the U.S. on January 19, 2020, residual archived samples from 7,389 routine blood donations collected by the American Red Cross from December 13, 2019 to January 17, 2020, from donors resident in nine states (California, Connecticut, Iowa, Massachusetts, Michigan, Oregon, Rhode Island, Washington, and Wisconsin) were tested at CDC for anti-SARS-CoV-2 antibodies. Specimens reactive by pan-immunoglobulin (pan Ig) enzyme linked immunosorbent assay (ELISA) against the full spike protein were tested by IgG and IgM ELISAs, microneutralization test, Ortho total Ig S1 ELISA, and receptor binding domain / Ace2 blocking activity assay.


Of the 7,389 samples, 106 were reactive by pan Ig. Of these 106 specimens, 90 were available for further testing. Eighty four of 90 had neutralizing activity, 1 had S1 binding activity, and 1 had receptor binding domain / Ace2 blocking activity >50%, suggesting the presence of anti-SARS-CoV-2-reactive antibodies. Donations with reactivity occurred in all nine states.


These findings suggest that SARS-CoV-2 may have been introduced into the United States prior to January 19, 2020.


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